TweetFollow Us on Twitter

Aug 95 Tips
Volume Number:11
Issue Number:8
Column Tag:Tips & Tidbits

Tips & Tidbits

By Steve Sisak, Contributing Editor

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

TIP OF THE MONTH

While developing an init that installs a system wide patch I needed a simple way to enable or disable it (forcing it to call the original patch) from the controlling application.

I found that the Gestalt manager could come in useful. In fact the procedure that installs a new selector, used in this case to check for the existence of the init, requires you to specify a response function which gets executed whenever the new selector is called. Being the function itself is part of the init, it is able to change the value of a status variable and return its state: assuming that the variable is a boolean. With two gestalt calls (max) it is possible to change the patch status. Follow some code fragments:

// global constants
#define kPatchSelector    'Test'   // must be OSType
#define kPatchNotPresent  0
#define kPatchPresent1

// INIT FRAGMENT
// INIT globals
Boolean gUsePatch = 3Dfalse;
SelectorFunctionUPPgGestaltSelectorFunction;

// install new gestalt selector
OSErr InstallGestalt(void) 
{
 OSErr  error;

 long   oldA4;
 oldA4 =3D SetUpA4();

 gGestaltSelectorFunction = 
 3DNewSelectorFunctionProc(PatchGestalt);
 error = 3DNewGestalt(kPatchSelector, 
 gGestaltSelectorFunction);

 RestoreA4(oldA4);
 return error;
}

//gestalt response function
pascal OSErr PatchGestalt(OSType gestaltSelector,long* 
 gestaltResponse)
{
    // use the global data in _this file_
 long oldA4;
 oldA4 = 3D SetUpA4();

 if (gUsePatch) { 
 *gestaltResponse = 3DkPatchNotPresent;
 gUsePatch = 3Dfalse;
 }
 else {
 *gestaltResponse = 3DkPatchPresent;
 gUsePatch=3Dtrue;
 }

 // restore the a4 world
 RestoreA4(oldA4);
 
 return noErr;
}
// APPLICATION FRAGMENT
OSErr TogglePatch(Boolean engage)
{
 OSErr  error=3DnoErr;
 long   gestaltFeature=3D0;

    //this call switches the = patch status
 error = 3DGestalt(kPatchSelector,&gestaltFeature);

 if (engage) {
    // was = already engaged; turn it back on
 if ((error = 3D = 3DnoErr) &&     
 (gestaltFeature = 3D = 3DkPatchNotPresent))
 error = 3DGestalt(kPatchSelector,&gestaltFeature);
 }
 else {
    // was = already disabled; turn it back off
 if ((error=3D=3DnoErr) && 
 (gestaltFeature=3D=3DkPatchPresent))
 error=3DGestalt(kPatchSelector,&gestaltFeature);
 }

 return error;
}

- Luigi Belverato
Milano, Italy

HandleMenuChoice

This tip may be a little obvious, I caught it right away, but some people may not have noticed the problem yet. Some people may have coded around it to begin with, but I didn't.

System 7.5 was the first time I saw the "Apple Menu Options" control panel. It is an extremely useful tool, I love it and use it constantly. But, there may be a slight difference in the way your application needs to handle menu highliting now that this control panel exists.

Here is the assumption I had been making for a long time: When the user selects a menu item, MenuSelect (and MenuKey) leave the menu title hilited. The application performs the indicated action and then unhilites the menu title. When no menu item is selected by the user (MenuSelect or MenuKey return 0L), the menu titles are not left hilited after the call.

The Apple Menu Options control panel is an exception. A menu selection in a submenu of the apple menu will leave the apple menu hilited, but MenuSelect will return 0L.

In the event handling code I have calls like this:

HandleMenuChoice( MenuSelect( event->where ) );
HandleMenuChoice( MenuKey( event->message & charCodeMask ) );

HandleMenuChoice looked like this:

void  HandleMenuChoice( long menuChoice )
{
 short  menu;
 short  item;
 
 if ( menuChoice != 0L ) {
 menu = HiWord( menuChoice );
 item = LoWord( menuChoice );
 
 switch ( menu ) {
 case mApple:
 HandleAppleChoice( item );
 break;
 case mFile:
 HandleFileChoice( item );
 break;
    // Other menus go here.
 }
 HiliteMenu( 0 );
 }
}

With this code, if the user selected an item in a submenu of the apple menu, the system will switch to the Finder and open the selected item (thanks to Apple Menu Options). When you switch back to your application, the apple menu will still be hilited (even if you call DrawMenuBar on the switch).

The work around is simple, call HiliteMenu( 0 ) even if MenuSelect returns 0L.

HandleMenuChoice should look like this:

void  HandleMenuChoice( long menuChoice )
{
 short  menu;
 short  item;
 
 if ( menuChoice != 0L ) {
 menu = HiWord( menuChoice );
 item = LoWord( menuChoice );
 
 switch ( menu ) {
 case mApple:
 HandleAppleChoice( item );
 break;
 case mFile:
 HandleFileChoice( item );
 break;
 // Other menus
 }
 // HiliteMenu( 0 ) was here
 }
 HiliteMenu( 0 );  // moved it to here
}

Your code may not look anything like this, but the idea is to call HiliteMenu( 0 ) even if MenuSelect returns 0L.

- Don Bresee
Los Angeles, CA

The Lost Paper

True story: I was once typing in some text in a word processor, when the computer suddenly crashed on me. I didn’t save a copy on to the hard-disk yet. I had to restart the computer and type it all over again. “But wait, the paper is still in the machine” I thought to myself. You see, when you restart all of the computer’s memory doesn’t get cleared, it just stays to what it was until it gets replaced with other information (usually, much like the behavior of a hard-disk). I had one thing going for me, I had MacsBug installed. Here are the steps I took to recover the paper:

First, I logged all of the work I was doing in MacsBug to a file. I did this using the “log” command. All you need to give the command is the name of the new file to log to. I named it “MyPaper” Good, now all of my MacsBug session will be on the hard-disk, so I can open it up with a normal text editor when I’m done.

Next, I needed to find where in memory my paper was. I did this using the “f” command. The first two parameters for this command is the range in memory in which you want MacsBug to search through. I wanted to search through all of my memory, which is 8 megs, so I typed in: “f 0 (400 * 400 * 8) “any string””. Where 0 is the beginning of memory and 8 megs is the top of it. The last parameter is the search string, balanced between two single quotes. I wanted to pick a distinct string, otherwise I would have hit other parts of memory that had it too, making the process take longer. I knew the word aardvark was mentioned in my paper, so I typed in this for the find command:

f 0 (400 * 400 * 8) “aardvark”

MacsBug then started searching for me. It came up with a small memory dump of something with the word arrdvark in it, but the words after it were not mine. (Which meant that I found another part of memory instead of my paper.) I then hit return to tell MacsBug to keep on searching. It then came up with a dump from my paper:

Searching for “aardvark” from 00000000 to 007FFFFF
  00358200  6161 7264 7661 726B  8000 0000 0000 002C  aardvark answer,

Which was very good news indeed! This told me that the string “aardvark answer” could be found at address 00358200. (I got this address from the leftmost number given.)

Now that I knew where it was, the rest my task would be easy. I used MacsBug’s display memory ASCII command to show me what came after it, by typing in: “dma 00358200”. (You might not have this command, in which case you’ll have to use plain old dm, instead of dma.) I hit return until my paper was done being displayed.

Note: You can subract a number from the address to see what was before it. For instance, subracting #200 from an address will give you the address of the first byte of the 200 byte block before it.

I then typed in “log” again, which closed my log. I finally went out of MacsBug and opened the log file with SimpleText. Remember, the log had my whole session, not just the paper, so I had to delete the addresses and such from it, (which really isn’t that hard to do, if you know how to use your mouse and your delete key efficiently). The paper was saved.

Warning: In your search you might stumble upon MacsBug’s very own memory, with its own copy of your search string. To get out of this recursive loop, start the search over again with the base search address being outside of MacsBug’s memory.

- Macneil Shonle
Yarmouth Maine, MacneilS@aol.com

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Capto 1.2.9 - $29.99
Capto (was Voila) is an easy-to-use app that takes capturing, recording, video and image editing to the next level. With an intelligent file manager and quick sharing options, Capto is perfect for... Read more
Opera 51.0.2830.40 - High-performance We...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
GarageSale 7.0.13 - Create outstanding e...
GarageSale is a slick, full-featured client application for the eBay online auction system. Create and manage your auctions with ease. With GarageSale, you can create, edit, track, and manage... Read more
1Password 6.8.7 - Powerful password mana...
1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
Evernote 7.0.1 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
MacUpdate Desktop 6.2.0 - $20.00
MacUpdate Desktop brings seamless 1-click app installs and version updates to your Mac. With a free MacUpdate account and MacUpdate Desktop 6, Mac users can now install almost any Mac app on... Read more
HoudahSpot 4.3.5 - Advanced file-search...
HoudahSpot is a versatile desktop search tool. Use HoudahSpot to locate hard-to-find files and keep frequently used files within reach. HoudahSpot will immediately feel familiar. It works just the... Read more
EtreCheck 4.0.4 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
WhatsApp 0.2.8361 - Desktop client for W...
WhatsApp is the desktop client for WhatsApp Messenger, a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for... Read more
iClock 4.2 - Customize your menubar cloc...
iClock is a menu-bar replacement for Apple's default clock but with 100x features. Have your Apple or Google calendar in the menubar. Have the day, date, and time in different fonts and colors in the... Read more

Latest Forum Discussions

See All

The best games like Florence
Florence is a great little game about relationships that we absolutely adored. The only problem with it is it's over a little too soon. If you want some other games with some emotional range like Florence, check out these suggestions: [Read more] | Read more »
Angry Birds Champions adds cash prizes t...
Collaborating with developer Rovio Entertainment, GSN Games has released a twist on the Angry Birds formula. Angry Birds Champions features the same bird-flinging gameplay, but now you can catapult Red and co for cash. | Read more »
Around the Empire: What have you missed...
148Apps is part of a family. A big family of sites that make sure you're always up to date with all the portable gaming news. Just like a real family, I guess. I don't know, my mum never told me anything about Candy Crush to be fair. [Read more] | Read more »
The Battle of Polytopia Guide - Tips for...
The addition of multiplayer to The Battle of Polytopia has catapulted the game from a fun enough time waster to a fully-fledged 4X experience on your phone. We've been playing quite a few matches over the past week or so, and we've put together a... | Read more »
All the best games on sale for iPhone an...
Hi there, and welcome to our round up of all the best games that are on sale for iOS at the moment. It's not a vintage week in terms of numbers, but I'm pretty sure that every single one of these is worth picking up if you haven't already played... | Read more »
Disc Drivin' 2 Guide - Tips for the...
We're all still playing quite a bit of Disc Drivin' 2 over here at 148Apps, and we've gotten pretty good at it. Now that we've spent some more time with the game and unlocked more powerups, check out some of these more advanced tips: | Read more »
Alto's Odyssey Guide - How to Tackl...
Alto’s Odyssey is a completely stunning and serene runner, but it can also be a bit tricky. Check out these to try and keep your cool while playing this endless runner: Don’t focus too much on tasks [Read more] | Read more »
Here's everything you need to know...
Alto's Odyssey is a really, really good game. If you don't believe me, you should definitely check out our review by clicking this link right here. It takes the ideas from the original Alto's Adventure, then subtly builds on them, creating... | Read more »
Alto's Odyssey (Games)
Alto's Odyssey 1.0.1 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: Just beyond the horizon sits a majestic desert, vast and unexplored. Join Alto and his friends and set off on an endless... | Read more »
Vainglory 5v5: Everything you need to kn...
Vainglory just got bigger. [Read more] | Read more »

Price Scanner via MacPrices.net

Apple AirPods in stock today for $159, free s...
Adorama reports stock of Apple AirPods today for $159 including free shipping, plus pay no sales tax outside of NY & NJ. See our Apple AirPod Price Tracker for the latest prices and stock status... Read more
Saturday Sale: Amazon offers 12″ 1.3GHz MacBo...
Amazon has Silver and Gold 2017 12″ 1.3GHz Retina MacBooks on sale for $250 off MSRP. Shipping is free: – 12″ 1.3GHz Silver MacBook: $1349.99 $250 off MSRP – 12″ 1.3GHz Gold MacBook: $1349.99 $250... Read more
Use your Apple Education discount and save up...
Purchase a new Mac using Apple’s Education discount, and take up to $400 off MSRP. All teachers, students, and staff of any educational institution with a .edu email address qualify for the discount... Read more
Apple Canada offers 2017 21″ and 27″ iMacs fo...
 Canadian shoppers can save up to $470 on the purchase of a 2017 current-generation 21″ or 27″ iMac with Certified Refurbished models at Apple Canada. Apple’s refurbished prices are the lowest... Read more
9″ iPads available online at Walmart for $50...
Walmart has 9.7″ Apple iPads on sale for $50 off MSRP for a limited time. Sale prices are for online orders only, in-store prices may vary: – 9″ 32GB iPad: $279.99 $50 off – 9″ 128GB iPad: $379.99 $... Read more
15″ Apple MacBook Pros, Certified Refurbished...
Save $360-$420 on the purchase of a 2017 15″ MacBook Pro with Certified Refurbished models at Apple. Apple’s refurbished prices are the lowest available for each model from any reseller. An standard... Read more
Amazon restocks MacBook Pros with models avai...
Amazon has restocked 15″ and 13″ Apple MacBook Pros with models on sale for up to $251 off MSRP. Shipping is free. Note that stock of some Macs may come and go (and some sell out quickly), so check... Read more
Lowest price of the year: 15″ 2.8GHz Apple Ma...
Amazon has the 2017 Space Gray 15″ 2.8GHz MacBook Pro on sale today for $251 off MSRP. Shipping is free: – 15″ 2.8GHz Touch Bar MacBook Pro Space Gray (MPTR2LL/A): $2148, $251 off MSRP Their price is... Read more
Apple restocks full line of Certified Refurbi...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
Lowest sale price available for 13″ 1.8GHz Ma...
Focus Camera has the 2017 13″ 1.8GHz/128GB Apple MacBook Air on sale today for $829 including free shipping. Their price is $170 off MSRP, and it’s the lowest price available for a current 13″... Read more

Jobs Board

*Apple* Media Products Commerce Engineering...
# Apple Media Products Commerce Engineering Manager Job Number: 56207285 Santa Clara Valley, California, United States Posted: 26-Jan-2018 Weekly Hours: 40.00 **Job Read more
Digital Platforms Lead, Today at *Apple* -...
# Digital Platforms Lead, Today at Apple Job Number: 56178747 Santa Clara Valley, California, United States Posted: 23-Feb-2018 Weekly Hours: 40.00 **Job Summary** Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.